Constructing tubular fuselages



Oct. 22,1946 v c. MILLER ETAL 2,409,782 I CONSTRUCTING TUBULAR FUSELAGES 311 a April 12, 1944 2 sheets-sheet 1 INVENTORS- Oct. 22, 1946. L. c. MILLER ETAL v CONSTRUCTING TUBULAR FUSELAGES Filed April 12, 1944 2 Sheets-Sheet 2 L. C. Millef G.E. Jc ar]eit INVENTORS.

BY [441 (1a a Patented Oct. 22, 1946 CON STRUCTING TUBULAR FUSELAGES Logan C. Miller, Ann Arbor, and George E.

Scarlett, Detroit, Mich.,

assignors to Ford Motor Company, Dearborn, Mich., a. corporation of Delaware Application Aprillz, 1944, .Serial No. 530,598

.1 rms nvention relates to the manufacture of a rframes; and, more particularly, to a method and appa atus for use in the construction of substantially tlibular fuselage components.

construction of those basically cylindrical alrframe components best exemplified by coin plete fuselage sections. It is true that in the larger fuselage sections, considerable simplificatlonof. construction is possible when the fuselage 1s divided into a number of. longitudinally extending panels which are separately constructed an thereafter joined together to form the compiece c mpon nt, shown iii eependillg application, Serial No. 487,2i8, filed May 17', 1943. rhis nethed of subdivision ermits easy access ferinterio'r riveting and installation of wiring, acce sories irectories; and, cfcourse, permits an ncrease in the number of persons who may ere simultaneously on each section. This metheu, owever, has certain limitations, particulariy when applied to the smaller fuselages or thee-mailer sections of large fuselages, a notable example of thelatter case being the extreme rear portion of the fuselage, usually referred to as atail cone. Here, even in a large bomber, iamuch sni'aller section is involved than in the remaining portion of the fuselage and it is not practicable to build it by subdivision. When the components are characterized by the smaller diameters, it is advisable-if at all possible-to construct them as a unit with one-piece bulkheads rather than rely upon the subdivision of However, in these smaller sections,

components. difficulties as to access to' the work and the number of persons who maybe employed simultaneously on the given component are emphasized and some steps must be taken to increase the accessibility and availability if these components are to be constructed readily as an integral unit.

Of course, from the earliest days of the art, it has been the custom to. construct all these fuselage components as integral members; and the subdivision method referred to above represents a later advance. Thus, the method disclosed here-while a return to first principles in a way-represents a substantial advance in that it confers some of the advantages accruing from sectional construction to the purely integral method. Another advantage is that it permits an accuracy of construction which results in sub stantial duplication of successive components which was not inherent in the prior methods of integral construction and without which a This invention finds particular application to Claims. (Cl. 29-286) 2 mass production schedule is a practical impossibility. Still another advantage of the present method is that it greatly increases the availability of the structureby which is meant that the number ofpersohs who can work on it simultaneously is increasedthereby cutting down the time of construction and reducing the'inter val in which any particular fixtur is occupied with the completion of one such structure. Not only is theavailability increased, but the acces sibility of the structure and the working conditions alike are improved.

With these and other objects in view, the invention consists in the arrangement, construction and combination of the various parts of the improved device andlsteps of the method as disclosed in the specification, claimed in the claims, and illustrated in the accompanying drawings in whichi.

Figure 1 is a perspective View of a fixture used in this invention shown in the primary assembly position.

Figure 2 is a similar view with the fixture shown in the secondary assembly position.

Figure 3 is an end elevation of the fixturaa portion of the wall being broken away to show the screw operating means.

Referring to Figure 1, III indicates generally a fuselage component which is substantially cylindrical in section and, in this instance, constitutes the tail cone of a heavy bomber. This according to usual construction, comprises a number of bulkheads or ring-frame structures ll, notched at I 2 adjacent their peripheries to receive the longerons l3 fastened by rivets thereto and the skin M, in turn, is riveted to the longerons l3 and the bulkheads II at I5. In the present instance, the forward end of the fuselage section I!) has a mating bulkhead which cannot be seen, as it is disposed against and bolted at to the end plate N5 of the fixture 9, but which is similar in form to the other bulkheads I l and subsequently mates with a similar mating bulkhead in the main fuselage section disposed forwardly and is bolted to it to complete the airframe fuselage structure. The rear part of the tail conexlil; since this is a military plane, is shown as having a mounting for a rotatable gun turret including a circular track I! (shown in Figure 2) and this is utilized in fixing the rear end of the fuselage component under consideration. It will .be understood that in other types of planes, other structural features may be utilized such as, a rudder post, stabilizer attaching means. some similar major element with inherent structural strength particularly suited for this purpose. In the present instance, the stub portions H! of the elevator are a fixed part of the fuselage component and the empennage assembly proper rests on and is secured to the substantially flat top plate I 9. Conditions may vary in other constructions, but again the methodifdepen'ds upon the use of a substantially continuous skin section along the top of the component to be built; and in the present case this is represented in its entirety in Figure 2 by the plate referred (which is quitefiat forwardly of the elevator stubs butlrounded zit- U to conform to the fuselage -,contour.from-there aft), extending from front torrea'ri along :the top of the component and initially secured in the position shown in the fixture 9.

The fixture 9 comprises a bed or base'ZI 'having four side columns 22 which enclose'a screw 23 and sleeve 24 jack arrangement, the sleeve 24 carrying the rectangular top frame 25. To this .frame -25 are permanently attached the hangers .25 which are adapted to support the elevator stubs a [.8 ,in predetermined ,position and the brackets 21 removablysecured in buttresses 53iand having angle plates,28,,which arebolted to .the ,top plate l9 through vprepllnched iholes thereby establishing the position ,of the plate which. comprisesethe ,upper portion .of the fuselage. component it] with respect to thefixture 9. In Figure-1, this. structurehis-largely brokenaway and shown in phantom toindicateedetails ofpthe fixture construction.

Thebed 2| of thefixture L9 hasaworkin fioor '29 and .inthecenter of this are .arnumber of bulkhead positioning ,steps 30 ,in the [form ,of successively raised projections 3| .having spaces 32 between them, these -.interv als corresponding to the bulkhead spacing and the general disposition of the steps following the contourof the lower surfaceof thefuselage section.. The projections support clamps 33 each comprising a fixedlbar 34 and -.a screw or springplunger 35 arrangedito secure a bulkhead inserted therebetween in predetermined elevation and alignment. The end projection has a ,hook clamp 36 holding the end bulkheadfi'l.

-At the rear end of the fixture 9,is the turret .track positioning cmeans .38, which includes a sector-,3!) conforming ,tothe shapeof the turret-5,

track If! (which .is temporarily secured to it during the iassembly step) andthis is fixed on legsAlJpivoted-at M tothehedli. Straps 42, ,a'lsofixedto the sectoizfifl, are, releasably secured ,to the -,rear columns .22 at 33. Ihusthe turret positioning means may be fixed i the position shown in Figure 2 for-.assembly; and, when this is completed,.detache dfrom the component and swung rearwardly and .down to the position shown in Figure 2.

The-end-plate i6 is rigidly-attached..to-..and "depends from the forward end of the. rectangular p frame 25 and is reinforced against longitudinal movement-by; the triangular shapedwebs 44. The plate i6 ,conforms--roughly-to-theoutline of thefuselage section, although it is somewhat larger in plan-andthe initial'bulkhead' is bolted directly against the inner surface of-said plate in predetermined position by the bolts 45.

A hook-shaped projection 66 looks into a recess' 41 on a boss' IB on the bed 2| when the frame 25 is in ,loweredposition, securely restraining theendplate l5. Thecolumns, 22 at opposite ends areconnected with a strut rod Mito further increase their rigidity when the top frame 25 is raised.

In operation, the fixture is set in the position shown in Figure 1. The initial bulkhead is bolted to the end plate It and the top plate is placed with the stub elevators E8 in the hangers 26 and itsforward edgeagainst the end plate I 6 to which it is bolted. It is then secured to the angle plates 28 on the brackets 2i by the bolts 50. Successive bulkheads H are angled under the top plate l9 into the spaces 32. They are then brought into vertical position at which their top portions are temporarily secured through prepunched z-rivet holes in=the-top plate and the bulkhead and itheir'bottom portions are clamped by the clamps:3-3:or'35. v.They are now in predetermined alignment andspacing and the temporarysecuring means are replaced by rivets.

Thetopmost two-thirds of the longerons l3 are then laid in the notches l2, with their front ends butting aga inst .the ,inne1asurface of th end plate l6, and the rear ends of .those ,in the lowerpart abutting against the turret track structure 154, which is built asta separate .,unit and carried by thepositioning means.38, and are riveted to the bulkheadsat eachintersection starting adjacent the end plate 1,6. The skin panels M are then laid over this skeleton'framework starting adjacent the end plate J6 and proceeding rearwardly and temporarily, secured to the longerons, bulkheadsandsidesvof plate IS. The horizontal extent ,of the skin panels placed is shown at ,5! in.-.1Tisure l. Theite nporary securing meansisuch as fCleco fasteners) are then replaced .by permanent rivets and the upper part ofthe fuselagesectioncis complete. The turret track positioning means .38 and the clamps 33 and 36 may be releasedand withdrawn as the component is now substantially self-sustaining.

As shown in Figurev 3,.the screw .ZJmay-now be p rated throu h t e worm wheel .51 .and worm 55, the latter beingmounted onna. cross shaft 55 operatedby the motor 58 ca1e being taken that uniform motion is transmitted to each corner of the frame ZBTand the frame .25 and the partiallycon pleted component raised. Since a large part of the ,skinandthe greater number of longerons have been .assembledand secured together, there is no chance for/the lower parts of the bulkheadsto be disarranged. The remaining longerons EZ, comprising thosein the botto m quarteror third of the structure,.are attached by butting them against the endplate 16 and thensecuring them to the successive bulkheads II at their points of intersection. When this is completed, the remainingskin panels are affixed and riveted and the structure ,-is finished. The end bulkheadis unbolted from the endplate l5 and thebrackets Zlfrom the top plate l9 and the buttresses 53 and,the completed component can be lifted out of the fixture by an overhead crane or other transport means fo urthe ac essin By d iyi dingthe work longitudinally, albeit still usin continuous ring bulkheads, theaccessibility is greatly increased. The provision made for locking the individual bulkheads at points, beneath the workingfloonlevel established bythe steps 3,0, permits free movement inside the ship without the imposition of stresses onthe skeleton st u tur W n h sbm enent i nth ra se pos t o it ln r t e i i ffieie tl a vanced,

the structural elements. The entire structure is based substantially on the end plate and each element (save the independently constructed and applied turret track structure 54) is startedfrom it. i The individual bulkheads are maintained in correct alignment, spacing and elevation by engagement with the top plate l9 and the clamps 33 and 36. The greater portion of the work on the exterior of the section can be done at a height best suited for maximum productive effort Some changes may be made in the arrangement, construction and combination of the various parts of the improved device without departing from the spirit of the invention, and it is the intention to cover by the claims such changes as may be reasonably included within the scope thereof.

The invention claimed is:

1, In an apparatus for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels, comprising, a base, vertical columns associated with said base, a frame supported by said vertical columns, means to elevate said frame with respect to said columns and said base, means on said frame to engage elements adjacent one surface of the component to be assembled therein, and readily releasable means on said base to secure other elements of said component adjacent the opposite surface of said component.

2. In an apparatus for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels, comprising, a base, vertical columns associated with said base, a frame supported by said vertical columns, means to elevate said frame with respect to said columns and said base, means on said frame to engage elements adjacent one surface of the component to be assembled therein, means on said base to receive and releasably secure successive bulkheads of said component.

3. In an apparatus for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels, comprising, a base, vertical columns associated with said base, a frame supported by said vertical columns, means to elevate said fram with respect to said columns and said. base, means on said frame to engage elements adjacent one surface of the component to be assembled therein and secure the same in predetermined elevation, means on said base to releasably secure successive bulkheads of .said component in predetermined spacing and alignment, and a vertically depending end panel secured to said fram and adapted to have an end bulkhead of said fuselage component releasably secured thereto.

4. In an apparatus for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels, comprising, a base, vertical columns associated with said base, a frame supported by said vertical columns, means to elevate said frame with respect to said columns and said base, means on said frame to engage elements adjacent one surface of the component to be assembled therein in predetermined alignment and elevation, means on said base to engage successive bulkheads of said components in predetermined spacing and alignment, an end panel .depending vertically from said frame and adapted to have an end bulkhead of said component releasably secured thereto, and means effective between said end plate and said base to secure said plate to said base when said frameis in lowered position.

5. In an apparatus for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels,

comprising, a base having a floor, vertical columns associated with said base, a frame supported by said vertical columns, means to elevate said frame with respect to said columns and said base, means. on saidframe to be secured to elements adjacent one surface of the componentto be assembled therein, a plurality of slots formed on said base, the spacing of such slots conforming to the spacing of the bulkheads in said components, clamping means adjacent said slots to se cure bulkheads therein in predetermined alignment and spacing when said frame is in lowered position, a substantial portion of said bulkheads being disposed beneath the adjacent floor level of said base when secured in position by said clamps.

6. In an apparatus for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels, comprising, a base, vertical columns associated with said base, a frame supported by said vertical columns, means to elevate said frame with respect to said columns and said base, means on said frame to secure elements adjacent one surface of the component to be assembled therein in predetermined elevation and alignment, a series of steps on said base arranged in increasing heights from one end of said base, spaces between said successive steps adapted to receive a portion 01 a bulkhead therein, clamping means on said steps adapted to engage said bulkhead received in said spaces, and an end plate vertically depending from said frame adjacent said end of said base and adapted to have an end bulkhead of said component secured thereto.

7. The structure in claim ii, which is further characterized in that a piloting means is pivotally supported at the opposite end of said base to engage an element of said component at the end opposite said bulkhead engaged by said end plate.

8. The structure of claim 6, which is further characterized in that further piloting means is pivotally supported at the opposite end of said base adapted to engage an element of said component at the end thereof opposite said end plate, and means effective between said base and said plate to lock said end plate with relation to said base when said frame is in lowered position.

9. In an apparatu for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels, comprising, a base, vertical columns associated with said base, a horizontal frame supported by said vertical columns and having an opening adequate to permit the vertical withdrawal of said component therefrom, means to elevate said frame with respect to said columns and said base, means on said frame to engage elements adjacent one surface of said component in predetermined elevation and alignment, readily releasable means on said base to engage successive bulkheads of said component in predetermined spacing and alignment, at least a portion of the bulkheads being disposed beneath the floor level of said base when said frame is in lowered position.

10. In an apparatus for assembling substantially tubular airframe fuselage components from bulkheads and longerons and exterior skin panels, comprising, a base, vertical columns associated with said base, a horizontal frame supported 7 by said vertical columns, elevating means between said columns and said frame efiective to elevate said frame a predetermined distance above said base, said frame having an opening sufficient to permit the vertical passage of Said component theretlirough, means on said frame to secure elements adjacent one surface of said component in predetermined alignment and elevation, a series of slots in the floor structur of said base, said slots adapted to receive successive bulkheads of 10 said component in predetermined alignment and sesame and with at least a substantial portion of said bulkhead being disposed beneath the adjacent floor level when said frame is in lowered position, an end plate vertically depending from said frame and adapted to have an end bulkhead of said fuselage section releasably secured directly thereto, the elevating means being effective on operation to lift said component with respect to said floor so that a considerable open working space is established therebetween.

LOGAN c. MILLER. GEO, E. SCARLETT. 

